I solved the issue. 

the following lines in the /etc/apache2/sites-available/site.name.conf files. php_value = … php_admin_value = …

All I had to do was to comment them.

The commands I used:

Create a backup copy of files

mkdir ~/sites_available_backup

cp -av /etc/apache2/sites-available/* ~/sites_available_backup

Commented the issue lines :

sed -i ‘s/php_admin_value/#php_admin_value/g’ /etc/apache2/sites-available/*

sed -i ‘s/php_value/#php__value/g’ /etc/apache2/sites-available/*

sudo systemctl restart apache2.service

walah! Issue Resolved